Unknown Variables
by Mikki13
Summary: Even Sarah has moments of vulnerability.


A/N: This one came to me late one night, when I was supposed to wake early for work the next day. It's amazing how gripping this show really is. ;-)

Disclaimer: I keep trying to charge them, but my credit card keeps coming up declined.

~*~

She wakes up early on Sunday mornings.

He can't remember when he first discovered this fact. He doesn't know what makes him follow her each time. The only thing he truly understands is that she knows he does it, but doesn't say a word. He never has been very good with stealth.

The first time she saw him, she cast him a look so lightning quick that he almost missed it. Only the slight tension in her shoulders and the momentary pause in her gait gave her away. But she continued unabated, and he followed her quietly. Or as quietly as he could, which really wasn't very quietly at all. (_He's pretty sure that stampeding buffalo have been known to be quieter.)_

The next day, she looked at him a little sharper than usual, her blue eyes piercing through his desperately casual façade. Almost as if she was testing him, trying to ascertain how much he had guessed. Trying to discover how much he knew.

But after two years of working with her, he's learned a few things. Like she doesn't like olives. And she can't stand rap music. And when she's got a secret – something that she holds to herself, deep inside, but that maybe she longs for someone else to know – the best thing to do is to pretend like nothing has changed. Because if nothing has changed, then she doesn't have to erect new walls to shut out unknown variables.

And to Sarah Walker, unknown variables are the worst kind of pitfalls. Because unknown variables have a way of puncturing through her carefully constructed mask and exposing her true self. A self she packed away long ago when she chose to join the CIA.

So when she pierces him with her calculating blue gaze, he simply smiles gently and pretends like nothing has changed.

But on those Sunday mornings, when the first rays of sunlight break through the night and reflect languidly off the smooth Burbank asphalt, she walks quickly down the streets and the mask wavers for the briefest of instances. And for a moment, Chuck can see the woman hidden behind the CIA agent. The real person hidden behind the life of lies. At those times, he can't help the raw ache that reverberates through his chest when he sees the look in her eyes – a deep, soulful gaze which she tries to fight back but which always resurfaces.

He doesn't know why she lets him follow her. Throughout their entire relationship, she has always tried to hold him at arm's length. She has repeatedly reminded him that what he wants can never be. But for some reason, the rules don't seem to apply here. Almost as if in the space between twilight and dawn, the line has become blurred and reality has become skewed.

Not that reality disappears altogether. He's seen her work her jaw a few times, certain that she's going to turn around and tell him to go home. To stop following her. To remind him that she's his handler and he's the asset, and he needs to respect the boundaries. But she never does. And he inevitably continues his Sunday morning strolls.

He's still not sure what keeps him coming back. Only that something about the look in her eyes, the way she doesn't object, tells him that he needs to continue. That maybe _she_ needs him to continue. Even if they never make contact. Even if they pretend that it never happens. Even if the distance between them remains, un-bridged and absolute.

Because he's content to stand at a distance, content that she knows he's there if she really does need him. It's the same game they've played for the last two years.

But on this particular Sunday morning, when she stops at her usual place at the edge of a grassy knoll in Valley Park, the dejected slump of her shoulders causes a sense of resolve to build in his gut. He watches her for a long moment as she sits on a park bench, staring out at the trees, the same emotional battle raging within her eyes. Before he can really contemplate what he's doing, he purses his lips, straightens his shoulders, and walks over to her bench, taking a seat.

Silence reigns for a long time, neither acknowledging the other's presence. The only indication that she's noticed he's there is given when she undetectably scoots a few millimeters closer to his side. She's still staring straight ahead when she finally speaks. "We used to go to the park when I was a kid," she says, her voice even and controlled. Even if her eyes speak volumes, her voice has been well trained. "My mom and I. Every Sunday morning."

Chuck starts, turning to stare at her. It's more information than she's ever given him, and for a moment he wonders if maybe he's fallen into a dream. But when she turns to look at him, he knows that it's entirely real. "She left when I was nine," she says, shrugging noncommittally. But the heavily guarded emotions still raging within her eyes tell him that it means more than she's willing to let on.

"I'm sorry," he replies softly, his features softening as his forehead creases with concern.

Again, she shrugs and turns to stare straight ahead. Even then, a shadow crosses her face and Chuck knows there's much more that she isn't telling him.

She isn't telling him that her mother died earlier that week. She isn't telling him that her mother's been fighting cancer for the last two months, ever since the beginnings of her Sunday morning ritual. She isn't telling him that she hasn't seen her mother since the day she walked out on her father when Sarah was only a kid.

To divulge all that would be to pierce her mask irreparably, to introduce too many unknown variables. And that's not something she's willing to do. Her training runs too deep to allow it.

Even so, Chuck really doesn't need to know. Long ago, he discovered that he could know her – really know _her_ – without ever being told a thing.

So when Sarah returns her gaze to the trees, all emotion now carefully concealed within the blue depths of her eyes, he knows to take her hand and thread his fingers into the negative space between her fingers, causing her to shiver imperceptibly. He knows to gently brush his thumb against the smooth skin of her hand, careful and caring in his embrace, as she allows herself to lean against his lithe arm. And he knows that tomorrow morning, when she pierces him with that same calculating look, he will pretend as if nothing has changed. As if everything remains the same.

Even if, in this one innocent moment, _everything_ has changed.

And while that change is imperceptible at first, over time it seeps into their relationship. Like when they're on a mission, pretending to be a couple, and she allows her hand to linger on his bare arm for a second longer than necessary. Or when she looks at him with unguarded eyes, the unknown variables cracking through her carefully constructed façade, and for just a moment, she allows him to step into her world. Or on Sunday mornings, when he jumps out of bed and eagerly heads for his front door, and she's waiting for him by the fountain, a soft smile stretched across her face.

Because she still wakes up early on Sunday mornings. She still makes the by now well-known trek to the park. Only now, he doesn't have to follow. Now, he simply walks contentedly by her side.

_Fin._


End file.
